1. Field of the Invention
The present invention relates to a catalyst for homo-polymerization or co-polymerization of ethylene, or more particularly to a high-activity titanium solid complex catalyst supported in a carrier containing magnesium the catalyst showing high catalytic activity high bulk density, and high hydrogen sensitivity.
2. Description of the Related Art
Catalysts containing magnesium for polymerization or co-polymerization of ethylene arc known to have very high catalytic activities and to accord good bulk density which are in turn suitable for liquid phase or gas phase polymerization. By liquid phase polymerization of ethylene, it denotes the polymerization process performed in such medium of bulk ethylene isopentane or hexane, and as for the important characteristics in consideration of the applicability of the catalyst used in this process they are as follows: high activity, bulk density the amount of molecules of low molecular weight dissolved in a medium etc. Furthermore, in most of these manufacturing processes, hydrogen is used to control the molecular weight. The changes in the molecular weight (hereinafter hydrogen sensitivity) according to the amount of hydrogen is another characteristic of a catalyst which is different per catalyst. The catalyst with high hydrogen sensitivity can control the molecular weight by using less amount of hydrogen at the time of the application of the process. As such, it provides more leeway with respect to the operation of the process.
Many of the titanium-based catalysts containing magnesium for olefin polymerization, and the manufacturing methods thereof have been reported. Especially many processes making use of magnesium solutions to obtain olefin polymerization catalysts of good bulk density have been known. There is a means of obtaining a magnesium solution by reacting magnesium compounds with such electron donors as alcohol amine cyclic ether or organic carboxylic acid in the presence of a hydrocarbon solvent. As for the cases of use of alcohol, they are disclosed in U.S. Pat. Nos. 4,330,649, and 5,106,807. Further the methods for production of catalysts containing magnesium by reacting a liquid magnesium solution with a halide compound such as titanium tetrachloride are well known. Such catalysts provide good bulk density, but there is much yet to be improved with respect to their catalytic activities and hydrogen sensitivity. In U.S. Pat. Nos. 4,477,639 and 4,518,706, a cyclic ether tetrahydrofurane was used as a solvent of the magnesium compound.
U.S. Pat. Nos. 4,847,227, 4,816,433, 4,829,037, 4,970,186, and 5,130,284 claimed the methods of producing olefin polymerization catalysts of good bulk density with superior polymerization activity due to the reaction of a titanium chloride compound with an electron donor compound such as magnesium alkoxide, dialkyl phthalate and phthaloyl chloride.
U.S. Pat. No. 5,459,116 reports the method of producing supported titanium solid catalysts by means of contact-reacting a titanium compound and a magnesium solution containing an ester having at least one hydroxy group as an electron donor. By using this method, it is possible to obtain a catalyst of superior polymerization activity and bulk density. However, there remain things to be improved with respect to hydrogen sensitivity.
U.S. Pat. No. 5,869,418 shows the method of increasing hydrogen sensitivity by using a dialkoxyphenylalkane in the propylene polymerization as an external electron donor, and the advantages of such method. However, the above effects were obtained by using the external electron donor in addition to the solid catalyst, and also it is limited to polymerization and co-polymerization of propylene.